Functionalized polymer

ABSTRACT

A method for providing a polymer having terminal functionality involves reacting a terminally active polymer with an α,β-ethylenically unsaturated compound that includes a group 2-13 element so as to provide a functionalized polymer. The resulting polymer exhibits enhanced interactivity with particulate fillers and can be used in the manufacture of vulcanizates.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. patent application Ser. No. 14/369,422which entered U.S. national stage on 27 Jun. 2014 and issued as U.S.Pat. No. 9,556,297 on 31 Jan. 2017, which is a national stage entryapplication of international application no. PCT/US2012/070898, filed 20Dec. 2012 and which claims the benefit of U.S. provisional patentapplication no. 61/582,277, filed 31 Dec. 2011.

BACKGROUND INFORMATION

Rubber goods such as tire treads often are made from elastomericcompositions that contain one or more reinforcing materials such as, forexample, particulate carbon black and silica; see, e.g., The VanderbiltRubber Handbook, 13th ed. (1990), pp. 603-04.

Good traction and resistance to abrasion are primary considerations fortire treads; however, motor vehicle fuel efficiency concerns argue for aminimization in rolling resistance, which correlates with a reduction inhysteresis and heat build-up during operation of the tire. (A reductionin hysteresis commonly is determined by a decrease in tan δ value at anelevated temperature, e.g., 50° or 60° C. Conversely, good wet tractionperformance commonly is associated with an increase in tan δ value at alow temperature, e.g., 0° C.) Reduced hysteresis and traction are, to agreat extent, competing considerations: treads made from compositionsdesigned to provide good road traction usually exhibit increased rollingresistance and vice versa.

Filler(s), polymer(s), and additives typically are chosen so as toprovide an acceptable compromise or balance of these properties.Ensuring that reinforcing filler(s) are well dispersed throughout theelastomeric material(s) both enhances processability and acts to improvephysical properties. Dispersion of fillers can be improved by increasingtheir interaction with the elastomer(s), which commonly results inreductions in hysteresis (see above). Examples of efforts of this typeinclude high temperature mixing in the presence of selectively reactivepro-moters, surface oxidation of compounding materials, surfacegrafting, and chemically modifying the polymer, typically at a terminusthereof.

Various elastomeric materials often are used in the manufacture ofvulcanizates such as, e.g., tire components. In addition to naturalrubber, some of the most commonly employed include high-cispolybutadiene, often made by processes employing catalysts, andsubstantially random styrene/butadiene interpolymers, often made byprocesses employing anionic initiators. Functionalities that can beincorporated into high-cis polybutadiene often cannot be incorporatedinto anionically initiated styrene/butadiene interpolymers and viceversa.

SUMMARY

In one aspect is provided a method for providing a polymer havingterminal functionality which includes a group 2-13 element. One or moreterminally active polymers are reacted with an α,β-ethylenicallyunsaturated compound that includes a group 2-13 element so as to providea functionalized polymer. The α,β-ethylenically unsaturated compound canbe represented by the general formula

where each R independently is a hydrogen atom or C₁-C₁₀ alkyl group, Mis a group 2-13 element, y and z are integers with the provisos that zis not zero and y+z is equal to a valence of M, and each X independentlyis OR¹, OC(O)R¹, C(O)OR¹ or NR¹ ₂ in which each R¹ independently is aC₁-C₃₀ alkyl group.

In another aspect is provided a polymer with terminal functionality thatincludes a group 2-13 element as part of the radical of anα,β-ethylenically unsaturated compound. The functionalized polymer canbe represented by the general formula

where R, M, y, z and X are defined as above, π is a polymer chain thatincludes unsaturated mer, and n is an integer of from 1 to 10 inclusive.Where z>1, the functionalized polymer can be considered to be coupled.

In the foregoing aspects, the polymer chains preferably include polyenemer units. In certain embodiments, the polyene(s) can be conjugateddiene(s). Where other types of mer are present, the conjugated diene mercan incorporate substantially randomly along the polymer chain. Thepolymer that includes polyene mer can be substantially linear.

The functionalized polymer can interact with various types ofparticulate filler including, for example, carbon black and silica.Compositions, including vulcanizates, that include particulate fillersand such polymers also are provided, as are methods of providing andusing such compositions.

Other aspects of the invention will be apparent to the ordinarilyskilled artisan from the detailed description that follows. To assist inunderstanding that description, certain defini-tions are providedimmediately below, and these are intended to apply throughout unless thesurrounding text explicitly indicates a contrary intention:

-   -   “polymer” means the polymerization product of one or more        monomers and is inclusive of homo-, co-, ter-, tetra-polymers,        etc.;    -   “mer” or “mer unit” means that portion of a polymer derived from        a single reactant molecule (e.g., ethylene mer has the general        formula —CH₂CH₂—);    -   “copolymer” means a polymer that includes mer units derived from        two reactants, typically monomers, and is inclusive of random,        block, segmented, graft, etc., copolymers;    -   “interpolymer” means a polymer that includes mer units derived        from at least two reactants, typically monomers, and is        inclusive of copolymers, terpolymers, tetra-polymers, and the        like;    -   “substituted” means one containing a heteroatom or functionality        (e.g., hydrocarbyl group) that does not interfere with the        intended purpose of the group in question;    -   “directly bonded” means covalently attached with no intervening        atoms or groups;    -   “polyene” means a molecule, typically a monomer, with at least        two double bonds located in the longest portion or chain        thereof, and specifically is inclusive of dienes, trienes, and        the like;    -   “polydiene” means a polymer that includes mer units from one or        more dienes;    -   “(meth)acrylate” means methacrylate or acrylate;    -   “phr” means parts by weight (pbw) per 100 pbw rubber;    -   “radical” means the portion of a molecule that remains after        reacting with another molecule, regardless of whether any atoms        are gained or lost as a result of the reaction;    -   “non-coordinating anion” means a sterically bulky anion that        does not form coordinate bonds with, for example, the active        center of a catalyst system due to steric hindrance;    -   “non-coordinating anion precursor” means a compound that is able        to form a non-coordinating anion under reaction conditions;    -   “ring system” means a single ring or two or more fused rings or        rings linked by a single bond, with the proviso that each ring        includes unsaturation;    -   “terminus” means an end of a polymeric chain;    -   “terminally active” means a polymer with a living or otherwise        very reactive (e.g., pseudo-living) terminus; and    -   “terminal moiety” means a group or functionality located at a        terminus.

Throughout this document, all values given in the form of percentagesare weight percentages unless the surrounding text explicitly indicatesa contrary intention. The relevant portion(s) of any patent orpublication mentioned herein is or are incorporated by reference.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

As apparent from the foregoing, the polymer can be described orcharacterized in a variety of ways. Generally, it includes unsaturatedmer units, typically units derived from one or more types of polyenes,and terminal functionality that includes a group 2-13 element. The group2-13 element advantageously can be provided as part of the radical of anα,β-ethylenically unsaturated compound. The polymer can be provided byreacting a terminally active polymer with an α,β-ethylenicallyunsaturated compound such as, for example, a (meth)acrylate.

The polymer can be elastomeric and can include mer units that includeethylenic unsaturation such as those derived from polyenes, particularlydienes and trienes (e.g., myrcene). Illustrative polyenes include C₄-C₁₂dienes, particularly conjugated dienes such as, but not limited to,1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene,2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene,2-methyl-1,3-pentadiene, 3-methyl-1,3-pentadiene,4-methyl-1,3-pentadiene, 2,4-hexadiene, and the like. In certainembodiments, the polymer includes only polyene mer and, in some of thoseembodiments, only conjugated diene mer.

Polyenes can incorporate into polymeric chains in more than one way.Especially for polymers intended for use in the manufacture of tiretreads, controlling this manner of incorporation can be desirable. Apolymer chain with an overall 1,2-microstructure, given as a numericalpercentage based on total polyene content, of from ˜10 to ˜80%,optionally from ˜25 to ˜65%, can be desirable for certain end useapplications. A polymer that has an overall 1,2-microstructure of nomore than ˜50%, preferably no more than ˜45%, more preferably no morethan ˜40%, even more preferably no more than ˜35%, and most preferablyno more than ˜30%, based on total polyene content, is considered to be“substantially linear.” For certain end use applications, however,keeping the content of 1,2-linkages to less than ˜7%, less than 5%, lessthan 2%, or less than 1% can be desirable.

Depending on the intended end use, one or more of the polymer chains caninclude pendent aromatic groups, which can be provided, for example,through incorporation of mer units derived from vinyl aromatics,particularly the C₈-C₂₀ vinyl aromatics such as styrene, α-methylstyrene, p-methyl styrene, the vinyl toluenes, the vinyl naphthalenes,and the like. When used in conjunction with one or more polyenes, merunits with pendent aromatic groups can constitute from ˜1 to ˜50%, from˜10 to ˜45%, or from ˜20 to ˜35%, of the polymer chain; themicrostructure of such interpolymers can be random, i.e., the mer unitsderived from each type of constituent monomer do not form blocks and,instead, are incorporated in an essentially non-repeating manner. Randommicrostructure can provide particular benefit in some end useapplications such as, e.g., rubber compositions used in the manufactureof tire treads.

Exemplary elastomers include interpolymers of one or more polyenes andstyrene such as, e.g., poly(styrene-co-butadiene), also known as SBR.

The number average molecular weight (M_(n)) of the polymer typically issuch that a quenched sample exhibits a gum Mooney viscosity (ML₄/100°C.) of from ˜2 to ˜150, more commonly from ˜2.5 to ˜125, even morecommonly from ˜5 to ˜100, and most commonly from ˜10 to ˜75.

The foregoing types of polymers can be made by emulsion polymerizationor solution polymerization, with the latter affording greater controlwith respect to such properties as randomness, microstructure, etc.Solution polymerizations have been performed since about the mid-20thcentury, so the general aspects thereof are known to the ordinarilyskilled artisan; nevertheless, certain aspects are provided here forconvenience of reference.

Depending on the nature of the polymer desired, the particularconditions of the solution polymerization can vary significantly. In thediscussion that follows, living polymerizations are described firstfollowed by a description of coordination catalyst-catalyzedpolymerizations. After these descriptions, the functionalization andprocessing of polymers so made are discussed.

Solution polymerization typically involves an initiator such as anorganolithium compound, particularly alkyllithium compounds. Examples oforganolithium initiators include N-lithio-hexamethyleneimine;n-butyllithium; tributyltin lithium; dialkylaminolithium compounds suchas dimethylaminolithium, diethylaminolithium, dipropylaminolithium,dibutyl-aminolithium and the like; dialkylaminoalkyllithium compoundssuch as diethylaminopropyl-lithium; and those trialkyl stanyl lithiumcompounds involving C₁-C₁₂, preferably C₁-C₄, alkyl groups.

Multifunctional initiators, i.e., initiators capable of forming polymerswith more than one living end, also can be used. Examples ofmultifunctional initiators include, but are not limited to,1,4-dilithiobutane, 1,10-dilithiodecane, 1,20-dilithioeicosane,1,4-dilithiobenzene, 1,4-dilithionaphthalene, 1,10-dilithioanthracene,1,2-dilithio-1,2-diphenylethane, 1,3,5-trilithio-pentane,1,5,15-trilithioeicosane, 1,3,5-trilithiocyclohexane,1,3,5,8-tetralithiodecane, 1,5,10,20-tetralithioeicosane,1,2,4,6-tetralithiocyclohexane, and 4,4′-dilithiobiphenyl.

In addition to organolithium initiators, so-called functionalizedinitiators also can be useful. These become incorporated into thepolymer chain, thus providing a functional group at the initiated end ofthe chain. Examples of such materials include lithiated aryl thioacetals(see, e.g., U.S. Pat. No. 7,153,919) and the reaction products oforganolithium compounds and, for example, N-containing organic compoundssuch as substituted aldimines, ketimines, secondary amines, etc.,optionally pre-reacted with a compound such as diisopropenyl benzene(see, e.g., U.S. Pat. Nos. 5,153,159 and 5,567,815).

Useful anionic polymerization solvents include various C₅-C₁₂ cyclic andacyclic alkanes as well as their alkylated derivatives, certain liquidaromatic compounds, and mixtures thereof. The ordinarily skilled artisanis aware of other useful solvent options and combinations.

In solution polymerizations, both randomization and vinyl content (i.e.,1,2-microstructure) can be increased through inclusion of a coordinator,usually a polar compound, in the polymerization ingredients. Up to 90 ormore equivalents of coordinator can be used per equivalent of initiator,with the amount depending on, e.g., the amount of vinyl content desired,the level of non-polyene monomer employed, the reaction temperature, andnature of the specific coordinator employed. Compounds useful ascoordinators include organic compounds that include a heteroatom havinga non-bonded pair of electrons (e.g., O or N). Examples include dialkylethers of mono- and oligo-alkylene glycols; crown ethers; tertiaryamines such as tetramethylethylene diamine; THF; THF oligomers; linearand cyclic oligomeric oxolanyl alkanes (see, e.g., U.S. Pat. No.4,429,091) such as 2,2-bis(2′-tetrahydrofuryl)propane, di-piperidylethane, hexamethylphosphoramide, N,N′-dimethylpiperazine,diazabicyclooctane, diethyl ether, tributylamine, and the like.

Although the ordinarily skilled artisan understands the conditionstypically employed in solution polymerization, a representativedescription is provided for convenience of the reader. The following isbased on a batch process, although extending this description to, e.g.,semi-batch or continuous processes is within the capability of theordinarily skilled artisan.

Solution polymerization typically begins by charging a blend ofmonomer(s) and solvent to a suitable reaction vessel, followed byaddition of a coordinator (if used) and initiator, which often are addedas part of a solution or blend; alternatively, monomer(s) andcoordinator can be added to the initiator. The procedure typically iscarried out under anhydrous, anaerobic conditions. The reactants can beheated to a temperature of up to ˜150° C. and agitated. After a desireddegree of conversion has been reached, the heat source (if used) can beremoved and, if the reaction vessel is to be reserved solely forpolymerizations, the reaction mixture is removed to apost-polymerization vessel for functionalization and/or quenching. Atthis point, the reaction mixture commonly is referred to as a “polymercement” because of its relatively high concentration of polymer.

Generally, polymers made according to anionic techniques can have aM_(n) of from ˜50,000 to ˜500,000 Daltons, although in certainembodiments the number average molecular weight can range from ˜75,000to ˜250,000 Daltons or even from ˜90,000 to ˜150,000 Daltons.

Certain end use applications call for polymers that have properties thatcan be difficult or inefficient to achieve via anionic (living)polymerizations. For example, in some applications, conjugated dienepolymers having high cis-1,4-linkage contents can be desirable.Polydienes can be prepared by processes using catalysts (as opposed tothe initiators employed in living polymerizations) and may displaypseudo-living characteristics, i.e., terminals that are not technicallyliving but which display many of the same reactive characteristics.

Some catalyst systems preferentially result in cis-1,4-polydienes, whileothers preferentially provide trans-1,4-polydienes. The ordinarilyskilled artisan is familiar with examples of each type of system. Theremainder of this description is based on a particular cis-specificcatalyst system, although this merely is for sake of exemplification andis not considered to be limiting to the functionalizing method andcompounds.

Exemplary catalyst systems can employ lanthanide metals which are knownto be useful for polymerizing conjugated diene monomers. Specifically,catalyst systems that include a lanthanide compound can be used toprovide cis-1,4-polydienes from one or more types of conjugated dienes.

Preferred lanthanide-based catalyst compositions are described in detailin, for example, U.S. Pat. No. 6,699,813 and patent documents citedtherein. The term “catalyst composition” is intended to encompass asimple mixture of ingredients, a complex of various ingredients that iscaused by physical or chemical forces of attraction, a chemical reactionproduct of some or all of the ingredients, or a combination of theforegoing. A condensed description is provided here for convenience andease of reference.

Exemplary lanthanide catalyst compositions include (a) a lanthanidecompound, an alkylating agent and a halogen-containing compound(although use of a halogen-containing compound is optional when thelanthanide compound and/or the alkylating agent contains a halogenatom); (b) a lanthanide compound and an aluminoxane; or (c) a lanthanidecompound, an alkylating agent, and a non-coordinating anion or precursorthereof.

Various lanthanide compounds or mixtures thereof can be employed. Thesecompounds preferably are soluble in hydrocarbon solvents such asaromatic hydrocarbons, e.g., benzene, toluene, xylenes,(di)ethylbenzene, mesitylene, and the like; aliphatic hydrocarbons suchas linear and branched C₅-C₁₀ alkanes, petroleum ether, kerosene,petroleum spirits, and the like; or cycloaliphatic hydrocarbons such ascyclopentane, cyclohexane, methylcyclopentane, methylcyclohexane, andthe like; although hydrocarbon-insoluble lanthanide compounds can besuspended in the polymerization medium. Preferred lanthanide compoundsinclude those which include at least one Nd, La, or Sm atom or thoseincluding didymium (a commercial mixture of rare-earth elements obtainedfrom monazite sand). The lanthanide atom(s) in the lanthanide compoundscan be in any of a number of oxidation states, although compounds havinga lanthanide atom in the +3 oxidation state typically are employed.Exemplary lanthanide compounds include carboxylates, organophosphates,organophosphonates, organophosphinates, xanthates, carbamates,dithiocarbamates, β-diketonates, alkoxides, aryloxides, halides,pseudo-halides, oxyhalides, and the like; numerous examples of each ofthese types of lanthanide compounds can be found in the aforementionedU.S. Pat. No. 6,699,813 as well as other similar patent documents.

Typically, the lanthanide compound is used in conjunction with one ormore alkylating agents, i.e., organometallic compounds that can transferhydrocarbyl groups to another metal. Typically, these agents areorganometallic compounds of electropositive metals such as Groups 1, 2,and 3 metals. Exemplary alkylating agents include organoaluminumcompounds such as those having the general formula AlR² _(o)Z_(3-o)(where o is an integer of from 1 to 3 inclusive; each R² independentlyis a monovalent organic group, which may contain heteroatoms such as N,O, B, Si, S, P, and the like, connected to the Al atom via a C atom; andeach Z independently is a hydrogen atom, a halogen atom, a carboxylategroup, an alkoxide group, or an aryloxide group) and oligomeric linearor cyclic aluminoxanes, which can be made by reactingtrihydro-carbylaluminum compounds with water, as well as organomagnesiumcompounds such as those having the general formula R³ _(m)MgZ_(2-m)where Z is defined as above, m is 1 or 2, and R³ is the same as R²except that each monovalent organic group is connected to the Mg atomvia a C atom.

Some catalyst compositions can contain compounds with one or more labilehalogen atoms. Preferably, the halogen-containing compounds are solublein hydrocarbon solvents such as those described above with respect tolanthanide compounds, although hydrocarbon-insoluble compounds can besuspended in the polymerization medium. Useful halogen-containingcompounds include elemental halogens, mixed halogens, hydrogen halides,organic halides, inorganic halides, metallic halides, organometallichalides, and mixtures of any two or more of the foregoing.

Other catalyst compositions contain a non-coordinating anion or anon-coordinating anion precursor. Exemplary non-coordinating anionsinclude tetraarylborate anions, particularly fluorinated tetraarylborateanions. Exemplary non-coordinating anion precursors include boroncompounds that include strong electron-withdrawing groups.

Catalyst compositions of the type just described have very highcatalytic activity for polymerizing conjugated dienes intostereospecific polydienes over a wide range of concentrations andratios, although polymers having the most desirable properties typicallyare obtained from systems that employ a relatively narrow range ofconcentrations and ratios of ingredients. Further, the catalystingredients are believed to interact to form an active catalyst species,so the optimum concentration for each ingredient can depend on theconcentrations of the other ingredients. The following molar ratios areconsidered to be relatively exemplary for a variety of different systemsbased on the foregoing ingredients:

-   -   alkylating agent to lanthanide compound (alkylating agent/Ln):        from ˜1:1 to ˜200:1, preferably from ˜2:1 to ˜100:1, more        preferably from ˜5:1 to ˜50:1;    -   halogen-containing compound to lanthanide compound (halogen        atom/Ln): from ˜1:2 to ˜20:1, preferably from ˜1:1 to ˜10:1,        more preferably from ˜2:1 to ˜6:1;    -   aluminoxane to lanthanide compound, specifically equivalents of        aluminum atoms on the aluminoxane to equivalents of lanthanide        atoms in the lanthanide compound (Al/Ln): from ˜50:1 to        ˜50,000:1, preferably from ˜75:1 to ˜30,000:1, more preferably        from ˜100:1 to ˜1,000:1; and    -   non-coordinating anion or precursor to lanthanide compound        (An/Ln): from ˜1:2 to ˜20:1, preferably from ˜3:4 to ˜10:1, more        preferably from ˜1:1 to ˜6:1.

The molecular weight of polydienes produced with lanthanide-basedcatalysts can be controlled by adjusting the amount of catalyst usedand/or the amounts of co-catalyst concentrations within the catalystsystem; polydienes having a wide range of molecular weights can beproduced in this manner. In general, increasing the catalyst andco-catalyst concentrations reduces the molecular weight of resultingpolydienes, although very low molecular weight polydienes (e.g., liquidpolydienes) require extremely high catalyst concentrations. Typically,this necessitates removal of catalyst residues from the polymer to avoidadverse effects such as retardation of the sulfur cure rate. U.S. Pat.No. 6,699,813 teaches that nickel compounds can be used as veryefficient molecular weight regulators. Including one or moreNi-containing compounds to lanthanide-based catalyst compositionsadvantageously permits easy regulation of the molecular weight of theresulting polydiene without significant negative effects on catalystactivity and polymer microstructure.

Various Ni-containing compounds or mixtures thereof can be employed. TheNi-containing compounds preferably are soluble in hydrocarbon solventssuch as those set forth above, although hydrocarbon-insolubleNi-containing compounds can be suspended in the polymerization medium toform the catalytically active species.

The Ni atom in the Ni-containing compounds can be in any of a number ofoxidation states including the 0, +2, +3, and +4 oxidation states,although divalent Ni compounds, where the Ni atom is in the +2 oxidationstate, generally are preferred. Exemplary Ni compounds includecarboxylates, organophosphates, organophosphonates, organophosphinates,xanthates, carbamates, dithiocarbamates, β-diketonates, alkoxides,aryloxides, halides, pseudo-halides, oxyhalides, organonickel compounds(i.e., compounds containing at least one C—Ni bond such as, for example,nickelocene, decamethylnickelocene, etc.), and the like.

The molar ratio of the Ni-containing compound to the lanthanide compound(Ni/Ln) generally ranges from ˜1:1000 to ˜1:1, preferably from ˜1:200 to˜1:2, and more preferably from ˜1:100 to ˜1:5.

These types of catalyst compositions can be formed using any of thefollowing methods:

-   -   (1) In situ. The catalyst ingredients are added to a solution        containing monomer and solvent (or simply bulk monomer). The        addition can occur in a stepwise or simultaneous manner. In the        case of the latter, the alkylating agent preferably is added        first followed by, in order, the lanthanide compound, the        nickel-containing compound (if used), and (if used) the        halogen-containing compound or the non-coordinating anion or        non-coordinating anion precursor.    -   (2) Pre-mixed. The ingredients can be mixed outside the        polymerization system, generally at a temperature of from about        −20° to ˜80° C., before being introduced to the conjugated diene        monomer(s).    -   (3) Pre-formed in the presence of monomer(s). The catalyst        ingredients are mixed in the presence of a small amount of        conjugated diene monomer(s) at a temperature of from about −20°        to ˜80° C. The amount of conjugated diene monomer can range from        ˜1 to ˜500 moles, preferably from ˜5 to ˜250 moles, and more        preferably from ˜10 to ˜100 moles, per mole of the lanthanide        compound. The resulting catalyst composition is added to the        remainder of the conjugated diene monomer(s) to be polymerized.    -   (4) Two-stage procedure.        -   (a) The alkylating agent is combined with the lanthanide            compound in the absence of conjugated diene monomer, or in            the presence of a small amount of conjugated diene monomer,            at a temperature of from about −20° to ˜80° C.        -   (b) The foregoing mixture and the remaining components are            charged in either a stepwise or simultaneous manner to the            remainder of the conjugated diene monomer(s) to be            polymerized.        -   (The Ni-containing compound, if used, can be included in            either stage.)            When a solution of one or more of the catalyst ingredients            is prepared outside the polymerization system in the            foregoing methods, an organic solvent or carrier is            preferably employed. Useful organic solvents include those            mentioned previously.

The production of cis-1,4-polydiene is accomplished by polymerizingconjugated diene monomer(s) in the presence of a catalytically effectiveamount of a catalyst composition. The total catalyst concentration to beemployed in the polymerization mass depends on the inter-play of variousfactors such as the purity of the ingredients, the polymerizationtemperature, the polymerization rate and conversion desired, themolecular weight desired, and many other factors; accordingly, aspecific total catalyst concentration cannot be definitively set forthexcept to say that catalytically effective amounts of the respectivecatalyst ingredients should be used. The amount of the lanthanidecompound used generally ranges from ˜0.01 to ˜2 mmol, preferably from˜0.02 to ˜1 mmol, and more preferably from ˜0.05 to ˜0.5 mmol per 100 gconjugated diene monomer. All other ingredients generally are added inamounts that are based on the amount of lanthanide compound (see thevarious ratios set forth previously).

Polymerization preferably is carried out in an organic solvent, i.e., asa solution or precipitation polymerization where the monomer is in acondensed phase. The catalyst ingredients preferably are solubilized orsuspended within the organic liquid. The concentration of monomerpresent in the polymerization medium at the beginning of thepolymerization generally ranges from ˜3 to ˜80%, preferably from ˜5 to˜50%, and more preferably from ˜10% to ˜30% by weight. (Polymerizationalso can be carried out by means of bulk polymerization conducted eitherin a condensed liquid phase or in a gas phase.)

Regardless of whether a batch, continuous, or semi-continuous process isemployed, the polymerization preferably is conducted with moderate tovigorous agitation under anaerobic conditions provided by an inertprotective gas such as N₂, Ar or He. The polymerization temperature mayvary widely, although typically a temperature of from ˜20° to ˜90° C. isemployed; heat can be removed by external cooling and/or cooling byevaporation of the monomer or the solvent. The polymerization pressureemployed may vary widely, although typically a pressure of from ˜0.1 to˜1 MPa is employed.

Where 1,3-butadiene is polymerized in a coordination catalyst system,the cis-1,4-polybutadiene generally has a M_(n), as determined by GPCusing polystyrene standards, of from ˜5,000 to ˜200,000 Daltons, from˜25,000 to ˜150,000 Daltons, or from ˜50,000 to ˜120,000 Daltons. Thepolydispersity of the polymers generally ranges from ˜1.5 to ˜5.0,typically from ˜2.0 to ˜4.0.

Resulting polydienes advantageously can have a cis-1,4-linkage contentof at least ˜60%, at least ˜75%, at least ˜90%, and even at least ˜95%,and a 1,2-linkage content of less than ˜7%, less than ˜5%, less than˜2%, and even less than ˜1%.

Both of the described polymerization processes advantageously result inpolymer chains that possess active (living or pseudo-living) terminals,which can be further reacted with one or more functionalizing agents soas to provide functionalized polymers. As described above,functionalization can enhance the interaction between the polymer andparticulate fillers in rubber compounds, thereby improving themechanical and dynamic properties of the resulting vulcanizates.

As mentioned above, the polymer includes terminal functionality. Thispolymer, hereinafter referred to as the functionalized polymer, can beprovided by reacting one or more terminally active polymer chains withan α,β-ethylenically unsaturated compound that includes a group 2-13element, i.e., elements with atomic numbers 4-5, 12-13, 20-31, 38-49,56, 71-81, 88 and 103-113.

Representative α,β-ethylenically unsaturated compounds include thosedefined by general formula I above. Within the genus defined by theformula, certain species can be preferred for some applications. Forexample, one subset of preferred compounds can be represented by thegeneral formula

where R″ is a hydrogen atom or C₁-C₃ alkyl group and the other variablesare defined as above in connection with formula (I). Formula (Ia)compounds include acrylates and (alk)acrylates (i.e., 2-alkyl-2-alkenoicacid esters). Preferred (alk)acrylates are methacrylates.

Other species within formula (I) are metal esters of 3-alkyl-2-alkenoicacid and 2,3-dialkyl-2-alkenoic acid, represented by formulas (Ib) and(Ic):

where each of M, X, y and z is defined as above in connection withformula (I) and each R′ independently is a C₁-C₁₀ alkyl group,preferably a C₁-C₃ alkyl group. Where R′ in formula (Ib) and each R′ informula (Ic) is a methyl group, the compounds are, respectively, metalesters of crotonic acid and angelic acid (where the R′ groups are trans)or tiglic acid (where the R′ groups are cis).

A subset of preferred compounds include those defined by general formula(I) where M is B (with 0≦y≦2), Al (with 0≦y≦2), or Zn (with 0≦y≦1).

Another subset of preferred compounds include those defined by generalformula (I) where each X is the same, i.e., each X is R¹, OC(O)R¹,C(O)OR¹ or NR¹ ₂ in which each R¹ is a C₁-C₃₀ alkyl group,advantageously a C₁-C₁₀ alkyl group, and preferably a C₁-C₆ alkyl group.Where each or at least one X is R¹, it preferably is a methyl, ethyl,propyl, or isobutyl group.

The foregoing preferences with respect to M and X can be combined intoany of general formulas (Ia)-(Ic) to provide specific preferredcompounds. Specific examples of such compounds are identified below inthe Examples section; these are not intended to be limiting and,instead, should be considered as illustrative of the types of compoundsthat can be useful and the benefits that the ordinarily skilled artisancan expect to receive from their use.

The amount of α,β-ethylenically unsaturated compound(s) added to thepolymer cement need not be particularly large. Relative to the moles ofactive termini (i.e., live or otherwise reactive polymer chain ends),from ˜1 to ˜10 moles of one or more α,β-ethylenically unsaturatedcompounds can be added to the polymer cement.

Because of the activity of, for example, carbanionic polymer chains,essentially all of the added α,β-ethylenically unsaturated compound(s)will add to polymer chain termini and will do so in an essentiallyproportional manner, e.g., addition of ˜3 moles of α,β-ethylenicallyunsaturated compound will result in addition of 3 mer ofα,β-ethylenically unsaturated compound to each active polymer chain.

The result of this reaction is a polymer with terminal functionality asdefined by general formula (II). In that formula, n can be an integer offrom 1 to 10 inclusive as well as all possible subcombination rangeswithin that range, for example, 1 to r where 2≦r≦9, 2 to s where 3≦s≦9,4 to t where 5≦t≦9, etc.

Where z>1 in a formula (I) compound, more than one polymer chain (π) canbe attached (indirectly) to M in formula (II). In such a case, theformula (I) compound radical acts a coupling agent, i.e., a locus formore than one attached polymer chain.

Reaction of such α,β-ethylenically unsaturated compounds with aterminally active polymer can be performed relatively quickly (˜1 to 300minutes) at moderate temperatures (e.g., 0° to 75° C.). Bondingtypically occurs between a C atom of the terminally active portion ofthe polymer chain and a Si or Sn atom of the (ring opened) cycliccompound, with one of the substituents of the Si or Sn atom optionallyacting as a leaving group.

Although typically not required, if desired, quenching can be conductedby stirring the polymer and an active hydrogen-containing compound, suchas an alcohol or acid, for up to ˜120 minutes at temperatures of from˜25° to ˜150° C.

Solvent can be removed from the quenched polymer cement by conventionaltechniques such as drum drying, extruder drying, vacuum drying or thelike, which may be combined with coagulation with water, alcohol orsteam, thermal desolvation, etc.; if coagulation is performed, ovendrying may be desirable.

The resulting polymer can be utilized in a tread stock compound or canbe blended with any conventionally employed tread stock rubber includingnatural rubber and/or non-functionalized synthetic rubbers such as,e.g., one or more of homo- and interpolymers that include justpolyene-derived mer units (e.g., poly(butadiene), poly(isoprene), andcopolymers incorporating butadiene, isoprene, and the like), SBR, butylrubber, neoprene, EPR, EPDM, acrylonitrile/butadiene rubber (NBR),silicone rubber, fluoroelastomers, ethylene/acrylic rubber, EVA,epichlorohydrin rubbers, chlorinated polyethylene rubbers,chlorosulfonated polyethylene rubbers, hydrogenated nitrile rubber,tetrafluoroethylene/propylene rubber and the like. When a functionalizedpolymer(s) is blended with conventional rubber(s), the amounts can varyfrom ˜5 to ˜99% of the total rubber, with the conventional rubber(s)making up the balance of the total rubber. The minimum amount depends toa significant extent on the degree of hysteresis reduction desired.

Amorphous silica (SiO₂) can be utilized as a filler. Silicas aregenerally classified as wet-process, hydrated silicas because they areproduced by a chemical reaction in water, from which they areprecipitated as ultrafine, spherical particles. These primary particlesstrongly associate into aggregates, which in turn combine less stronglyinto agglomerates. “Highly disper-sible silica” is any silica having avery substantial ability to de-agglomerate and to disperse in anelastomeric matrix, which can be observed by thin section microscopy.

Surface area gives a reliable measure of the reinforcing character ofdifferent silicas; the Brunauer, Emmet and Teller (“BET”) method(described in J. Am. Chem. Soc., vol. 60, p. 309 et seq.) is arecognized method for determining surface area. BET surface area ofsilicas generally is less than 450 m²/g, and useful ranges of surfaceinclude from ˜32 to ˜400 m²/g, ˜100 to ˜250 m²/g, and ˜150 to ˜220 m²/g.

The pH of the silica filler is generally from ˜5 to ˜7 or slightly over,preferably from ˜5.5 to ˜6.8.

Some commercially available silicas which may be used include Hi-Sil™215, Hi-Sil™ 233, and Hi-Sil™ 190 (PPG Industries, Inc.; Pittsburgh,Pa.). Other suppliers of commercially available silica include GraceDavison (Baltimore, Md.), Degussa Corp. (Parsippany, N.J.), RhodiaSilica Systems (Cranbury, N.J.), and J.M. Huber Corp. (Edison, N.J.).

Silica can be employed in the amount of ˜1 to ˜100 phr, preferably in anamount from ˜5 to ˜80 phr. The useful upper range is limited by the highviscosity that such fillers can impart.

Other useful fillers include all forms of carbon black including, butnot limited to, furnace black, channel blacks and lamp blacks. Morespecifically, examples of the carbon blacks include super abrasionfurnace blacks, high abrasion furnace blacks, fast extrusion furnaceblacks, fine furnace blacks, intermediate super abrasion furnace blacks,semi-reinforcing furnace blacks, medium processing channel blacks, hardprocessing channel blacks, conducting channel blacks, and acetyleneblacks; mixtures of two or more of these can be used. Carbon blackshaving a surface area (EMSA) of at least 20 m²/g, preferably at least˜35 m²/g, are preferred; surface area values can be determined by ASTMD-1765 using the CTAB technique. The carbon blacks may be in pelletizedform or an unpelletized flocculent mass, although unpelletized carbonblack can be preferred for use in certain mixers.

The amount of carbon black can be up to ˜50 phr, with ˜5 to ˜40 phrbeing typical. When carbon black is used with silica, the amount ofsilica can be decreased to as low as ˜1 phr; as the amount of silicadecreases, lesser amounts of the processing aids, plus silane if any,can be employed.

Elastomeric compounds typically are filled to a volume fraction, whichis the total volume of filler(s) added divided by the total volume ofthe elastomeric stock, of ˜25%; accordingly, typical (combined) amountsof reinforcing fillers, i.e., silica and carbon black, is ˜30 to 100phr.

When silica is employed as a reinforcing filler, addition of a couplingagent such as a silane is customary so as to ensure good mixing in, andinteraction with, the elastomer(s). Generally, the amount of silane thatis added ranges between ˜4 and 20%, based on the weight of silica fillerpresent in the elastomeric compound.

Coupling agents can have a general formula of A-T-G, in which Arepresents a functional group capable of bonding physically and/orchemically with a group on the surface of the silica filler (e.g.,surface silanol groups); T represents a hydrocarbon group linkage; and Grepresents a functional group capable of bonding with the elastomer(e.g., via a sulfur-containing linkage). Such coupling agents includeorganosilanes, in particular polysulfurized alkoxysilanes (see, e.g.,U.S. Pat. Nos. 3,873,489, 3,978,103, 3,997,581, 4,002,594, 5,580,919,5,583,245, 5,663,396, 5,684,171, 5,684,172, 5,696,197, etc.) orpolyorganosiloxanes bearing the G and A functionalities mentioned above.An exemplary coupling agent isbis[3-(triethoxysilyl)propyl]-tetrasulfide.

Addition of a processing aid can be used to reduce the amount of silaneemployed; see, e.g., U.S. Pat. No. 6,525,118 for a description of fattyacid esters of sugars used as processing aids. Additional fillers usefulas processing aids include, but are not limited to, mineral fillers,such as clay (hydrous aluminum silicate), talc (hydrous magnesiumsilicate), and mica as well as non-mineral fillers such as urea andsodium sulfate. Preferred micas contain principally alumina, silica andpotash, although other variants also can be useful. The additionalfillers can be utilized in an amount of up to ˜40 phr, typically up to˜20 phr.

Other conventional rubber additives also can be added. These include,for example, process oils, plasticizers, anti-degradants such asantioxidants and antiozonants, curing agents and the like.

All of the ingredients can be mixed using standard equipment such as,e.g., Banbury or Brabender mixers. Typically, mixing occurs in two ormore stages. During the first stage (often referred to as themasterbatch stage), mixing typically is begun at temperatures of ˜120°to ˜130° C. and increases until a so-called drop temperature, typically˜165° C., is reached.

Where a formulation includes silica, a separate re-mill stage often isemployed for separate addition of the silane component(s). This stageoften is performed at temperatures similar to, although often slightlylower than, those employed in the masterbatch stage, i.e., ramping from˜90° C. to a drop temperature of ˜150° C.

Reinforced rubber compounds conventionally are cured with ˜0.2 to ˜5 phrof one or more known vulcanizing agents such as, for example, sulfur orperoxide-based curing systems. For a general disclosure of suitablevulcanizing agents, the interested reader is directed to an overviewsuch as that provided in Kirk-Othmer, Encyclopedia of Chem. Tech., 3ded., (Wiley Interscience, New York, 1982), vol. 20, pp. 365-468.Vulcanizing agents, accelerators, etc., are added at a final mixingstage. To ensure that onset of vulcanization does not occur prematurely,this mixing step often is done at lower temperatures, e.g., starting at˜60° to ˜65° C. and not going higher than ˜105° to ˜110° C.

The following non-limiting, illustrative examples provide the readerwith detailed conditions and materials that can be useful in thepractice of the present invention.

EXAMPLES Examples 1-4: Metal Ester Compounds

In a N₂-purged vessel equipped with a stirrer was added ˜25 mL of a 0.68M solution of triisobutyl aluminum in hexane. This vessel was maintainedat −78° C. while ˜13.7 mL of a 1.24 M solution of acrylic acid in THFwas added in dropwise fashion. After addition was complete, the contentsof the vessel were allowed to come to room temperature slowly and thenstirred for an additional ˜10 minutes. Proton NMR spectroscopy resultswere consistent with diisobutylaluminum acrylate. The colorless solution(˜0.44 M) is designated Example 1 in the remaining examples.

In a N₂-purged vessel equipped with a stirrer was added ˜20 mL of a 1.0M solution of diethyl zinc in hexane. The vessel was maintained at −78°C. while ˜20 mL of a 1.0 M solution of acrylic acid in THF was added indropwise fashion. After addition was complete, the contents of thevessel were warmed and stirred as described in the preceding paragraph.Proton NMR spectroscopy results were consistent with ethyl zincacrylate. The colorless solution (˜0.5 M) is designated Example 2 below.

In an Ar-purged three-necked flask equipped with a stirrer and apressure equal-izing funnel was added ˜17 mL of a 1.0 M solution oftriethylborane in THF. The vessel was cooled to −78° C. before a mixtureof 1.16 mL (17 mmol) acrylic acid (after passing through an inhibitorremover) and 5 mL dry THF was added to the funnel and dropped into theflask over ˜10 minutes. After addition was complete, the flask wasremoved from the cooling bath and its contents slowly allowed to come toroom temperature and then stirred for an additional ˜60 minutes. Thissolution of diethyl boron acrylate in THF, designated Example 3 below,was used without further purification.

In a N₂-purged vessel equipped with a stirrer was added ˜25 mL of a 0.68M solution of triisobutyl aluminum in hexane. This vessel was maintainedat −78° C. while ˜17 mL of a 1.0 M solution of crotonic acid in THF wasadded in dropwise fashion. After addition was complete, the contents ofthe vessel were warmed and stirred as in Example 1 above. Proton NMRspectroscopy results were consistent with diisobutylaluminum crotonate.The colorless solution (˜0.4 M) is designated as Example 4 in theremaining examples.

The metal ester compounds were used in the remaining examples to providefunctionalized polymers. The polymers were prepared in dried glassvessels previously sealed with extracted septum liners and perforatedcrown caps under a positive N₂ purge unless otherwise indicated. Thepolymerizations employed hexane, butadiene solutions (variousconcentrations in hexane), styrene solutions (various concentrations inhexane), n-butyllithium (various concentrations in hexane),2,2-bis(2′-tetrahydrofuryl)propane solution (various concentrations inhexane, stored over CaH₂), and 2,6-di-tert-butyl-4-methylphenol (BHT)solution in hexane.

Examples 5-8: Aluminum Acrylate Functionalized Interpolymers

To a N₂-purged reactor equipped with a stirrer was added 1.55 kg hexane,0.37 kg styrene solution (34.5% by wt.), and 2.29 kg butadiene solution(22.3% by wt.). The reactor was charged with 3.17 mL of 1.68 Mn-butyllithium solution, followed by 1.2 mL of 1.6 M2,2-bis(2′-tetrahydrofuryl)propane solution. The reactor jacket washeated to 50° C. and the contents stirred for ˜75 minutes.

The polymer cement, which had a styrene content (relative to total mercontent) of 20.8% and a vinyl content (i.e., 1,2-microstructure) of54.9%, was dropped into four evacuated bottles. One of these (sample 5)was terminated with isopropanol before being coagulated with isopropanolcontaining BHT.

The portions of the polymer cement in the other three bottles werereacted with varying amounts of the diisobutylaluminum acrylate fromExample 1,

-   -   sample 6—1:1,    -   sample 7—3:1, and    -   sample 8—5:1,        with the ratios representing the molar ratio of acrylate to        lithium initiator, which essentially corresponds to the moles of        live polymer chains. The bottles containing samples 6-8 were        agitated for ˜30 minutes at room temperature before water (1, 3        and 5 g, respectively, per 400 g polymer cement) was added to        terminate the living chain ends. These polymer cements were        coagulated with isopropanol containing BHT similarly to sample        5.

Each of samples 5 to 8 was drum dried. Properties of the control polymer(sample 5) and the functionalized polymers (samples 6-8) are summarizedin Table 1, where M_(p) represents peak molecular weight.

Cold flow testing was performed using a Scott™ tester (PTES EquipmentServices, Inc.; Johnston, R.I.). Samples were prepared by melt pressing2.5 g of polymer at 100° C. for 20 minutes in a mold using a preheatedpress. The resulting cylindrical samples, which had a uniform thicknessof ˜12 mm, were allowed to cool to room temperature before being removedfrom the mold. Samples were placed individually under the weight of acalibrated 5 kg weight. Sample thicknesses were recorded as a functionof time, starting from the time that the weight was released. Samplethickness at the conclusion of ˜30 minutes generally is considered to bean acceptable indicator of resistance to cold flow for this type ofpolymer, and that is the value presented in the following table.

TABLE 1 Properties of polymers from Examples 5-8 5 6 7 8 M_(n) (kg/mol)117 134 231 135 M_(w)/M_(n) 1.05 1.23 1.63 1.51 M_(p) (kg/mol) 121 122248 246 T_(g) (° C.) −35.6 −36.1 −35.8 −36.1 % coupling 1.4 22.8 * 51.7cold flow (mm) 2.2 4.6 7.1 6.8 * Indefinite.

Examples 9-12: Zinc Acrylate Functionalized Interpolymers

The polymerization procedure from Examples 5-8 was essentially repeatedusing 4.38 kg hexane, 1.20 kg styrene solution (34.0% by wt.), 7.93 kgbutadiene solution (20.6% by wt.), 10.63 mL of 1.60 M n-butyllithiumsolution, and 3.5 mL of 1.6 M 2,2-bis(2′-tetrahydro-furyl)propanesolution. The contents were stirred for ˜60 minutes after the reactorjacket was heated to 50° C.

The polymer cement, which had a styrene content of 20.1% and a vinylcontent of 57.6%, was dropped into four evacuated bottles. One of these(sample 9) was terminated with isopropanol and then coagulated withisopropanol containing BHT.

The portions of the polymer cement in the other three bottles werereacted with the ethyl zinc acrylate from Example 2, using the same 1:1,3:1 and 5:1 ratios employed in Examples 5-8.

These polymer cements were reacted and processed identically to thosefrom Examples 5-8. Properties of the control polymer (sample 9) and thefunctionalized polymers (samples 10-12) are summarized in Table 2.(Mooney viscosity (ML₁₊₄) values were determined with an AlphaTechnologies™ Mooney viscometer (large rotor) using a one-minute warm-uptime and a four-minute running time.)

TABLE 2 Properties of polymers from Examples 9-12 9 10 11 12 M_(n)(kg/mol) 113 120 147 183 M_(w)/M_(n) 1.04 1.54 2.29 1.97 M_(p) (kg/mol)117 115 117 236 ML₁₊₄ @ 100° C. 12.0 25.5 60.5 76.3 t₈₀ (sec) 0.92 1.362.44 2.61 % coupling 1.4 10.8 41.1 70.1 cold flow (mm) 2.3 3.1 5.5 6.4

Examples 13-16: Boron Acrylate Functionalized Interpolymers

The polymerization procedure from Examples 5-8 was essentially repeatedusing 3.91 kg hexane, 0.97 kg styrene solution (34.0% by wt.), 6.36 kgbutadiene solution (21.4% by wt.), 8.59 mL of 1.65 M n-butyllithiumsolution, and 5.14 mL of 1.0 M 2,2-bis(2′-tetrahydro-furyl)propanesolution. The reactor jacket was heated to ˜71° C., and its contentswere stirred for ˜30 minutes after a peak temperature was reached.

The polymer cement, which had a styrene content of 20.2% and a vinylcontent of 57.6%, was dropped into four evacuated bottles. One of these(sample 13) was terminated with isopropanol and then coagulated withisopropanol containing BHT.

The portions of the polymer cement in the other three bottles werereacted with the diethyl boron acrylate from Example 3, using the same1:1, 3:1 and 5:1 ratios employed in Examples 5-8.

These polymer cements were reacted and processed identically to thosefrom Examples 5-8. Properties of the control polymer (sample 13) and thefunctionalized polymers (samples 14-16) are summarized in Table 3.

TABLE 3 Properties of polymers from Examples 13-16 13 14 15 16 M_(n)(kg/mol) 133 139 185 187 M_(w)/M_(n) 1.1 1.2 1.4 1.4 M_(p) (kg/mol) 138138 139 140 ML₁₊₄ @ 100° C. 25.6 31.0 63.8 65.8 t₈₀ (sec) 1.0 1.2 2.12.2 % coupling 4 9 49 50 cold flow (mm) 2.9 3.1 4.5 4.5

Examples 17-19: Aluminum Crotonate Functionalized Interpolymers

The polymerization procedure from Examples 5-8 was essentially repeatedusing 4.53 kg hexane, 1.17 kg styrene solution (35.0% by wt.), 7.81 kgbutadiene solution (20.9% by wt.), 10.31 mL of 1.65 M n-butyllithiumsolution, and 3.51 mL of 1.6 M 2,2-bis(2′-tetrahydro-furyl)propanesolution. The contents were stirred for ˜80 minutes after the reactorjacket was heated to 50° C.

The polymer cement, which had a styrene content of 19.9% and a vinylcontent of 56.9%, was dropped into three evacuated bottles. One of these(sample 17) was terminated with isopropanol and then coagulated withisopropanol containing BHT.

The portions of the polymer cement in the other two bottles were reactedwith the diisobutyl aluminum crotonate from Example 4 using,respectively, 1:1 and 3:1 ratios relative to moles of Li.

These polymer cements were reacted and processed identically to thosefrom Examples 5-8. Properties of the control polymer (sample 17) and thefunctionalized polymers (samples 18-19) are summarized in Table 3.

TABLE 4 Properties of polymers from Examples 17-19 17 18 19 M_(n)(kg/mol) 121 168 166 M_(w)/M_(n) 1.05 1.27 1.30 M_(p) (kg/mol) 126 263262 ML₁₊₄ @ 100° C. 15.9 76.4 82.4 t₈₀ (sec) 0.95 2.50 2.36 % coupling1.4 47.1 63.8 cold flow (mm) 2.3 4.9 5.0

Examples 20-42: Filled Compositions and Vulcanizates

The polymers from Examples 5-8, 9-12, 13-16 and 17-19 were used to makefilled compositions (compounds), employing the formulation shown inTable 5a (silica as sole particulate filler) and Table 5b (carbon blackas sole particulate filler) whereN-phenyl-N′-(1,3-dimethylbutyl)-p-phenylenediamine (6PPD) acts as anantioxidant and 2,2′-dithiobis(benzo-thiazole) (MBTS),N-tert-butylbenzothiazole-2-sulfenamide (TBBS) andN,N′-diphenylguanidine (DPG) act as accelerators. Black oil is anextender oil that contains a relatively low amount of polycyclicaromatic compounds.

TABLE 5a Silica compound formulation Amount (phr) Masterbatch syntheticpolymer 80 natural rubber 20 silica 52.5 wax 2 6PPD 0.95 stearic acid 2black oil 10 Re-mill 60% disulfide 5 silane on carrier silica 2.5 Finalsulfur 1.5 ZnO 2.5 MBTS 2 TBBS 0.7 DPG 1.4 TOTAL 183.05

TABLE 5b Carbon black compound formulation Amount (phr) Masterbatchsynthesized polymer 100 carbon black 50 (N343 type) wax 2 6PPD 0.95stearic acid 2 black oil 10 Final sulfur 1.5 ZnO 2.5 TBBS 0.5 MBTS 0.5DPG 0.3 TOTAL 170.25

Compounds were cured for ˜15 minutes at 171° C. Results of physicaltesting on these compounds are shown in the following tables:

Table 6a: Examples 20-23—silica compounds, polymers from Examples 5-8

Table 6b: Examples 24-27—silica compounds, polymers from Examples 9-12

Table 6c: Examples 28-31—silica compounds, polymers from Examples 13-16

Table 6d: Examples 32-34—silica compounds, polymers from Examples 17-19

Table 7a: Examples 35-38—carbon black compounds, polymers from Examples9-12

Table 7b: Examples 39-42—carbon black compounds, polymers from Examples13-16

Results of physical testing on vulcanizates made from these polymersalso are summarized in these tables. For the “Temp. sweep” line, the toprow of data are from measurements at 0° C. while the bottom row are frommeasurements at 60° C.

Tensile mechanical properties were determined using the standardprocedure described in ASTM-D412; Payne effect (ΔG′, i.e., thedifference between G′ at 0.25% strain and at 14% strain) and hysteresis(tan δ) data were obtained from dynamic experiments conducted at 60° C.and 10 Hz (strain sweep). With respect to tensile properties, M_(J) ismodulus at J % elongation, T_(b) is tensile strength at break, and E_(b)is percent elongation at break.

TABLE 6a Compound & vulcanizate properties, aluminum acrylate (silicacompound) 20 21 22 23 synthetic polymer 5 6 7 8 (sample no.) ML₁₊₄ @130° C. (final) 18.9 26.9 48.8 44.8 Tensile @ 23° C. (final, unaged) M₅₀(MPa) 1.35 1.36 1.21 1.21 T_(b) (MPa) 12.9 14.6 17.4 14.5 E_(b) (%) 468504 598 532 Tensile @ 100° C. (final, unaged) M₅₀ (MPa) 1.28 1.14 1.131.13 T_(b) (MPa) 7.4 6.9 7.3 7.8 E_(b) (%) 310 300 325 342 Strain sweep(60° C., 10 Hz, 5% strain, final) G′ (MPa) 4.21 3.15 2.69 2.81 G″ (MPa)0.64 0.37 0.24 0.26 tan δ 0.1526 0.1188 0.0882 0.0941 ΔG′ (MPa) 4.722.24 0.97 1.24 Bound rubber (%) 21.2 26.2 33.9 32.7

TABLE 6b Compound & vulcanizate properties, zinc acrylate (silicacompound) 24 25 26 27 synthetic polymer 9 10 11 12 (sample no.) ML₁₊₄ @130° C. (final) 18.1 20.8 35.1 44.2 Tensile @ 23° C. (final, unaged) M₅₀(MPa) 2.03 2.16 2.08 2.19 T_(b) (MPa) 14.6 14.1 15.8 13.6 E_(b) (%) 309294 312 283 Tensile @ 100° C. (final, unaged) M₅₀ (MPa) 1.94 1.95 2.032.04 T_(b) (MPa) 6.6 7.3 7.7 8.2 E_(b) (%) 178 190 192 205 Strain sweep(60° C., 10 Hz, 5% strain, final) G′ (MPa) 3.29 3.17 2.75 2.72 tan δ0.167 0.154 0.120 0.119 ΔG' (MPa) 3.89 3.20 1.77 1.71 Bound rubber (%)25.1 30.8 45.0 47.4

TABLE 6c Compound & vulcanizate properties, boron acrylate (silicacompound) 28 29 30 31 synthetic polymer (sample no.) 13 14 15 16 ML₁₊₄ @130° C. (final) 22.2 23.8 43.9 43.6 Tensile @ 23° C. (final, unaged) M₅₀(MPa) 2.09 2.16 2.14 2.06 T_(b) (MPa) 11.1 15.3 14.6 15.9 E_(b) (%) 249305 302 321 Tensile @ 100° C. (final, unaged) M₅₀ (MPa) 2.00 2.05 2.112.09 T_(b) (MPa) 6.9 7.6 8.3 7.4 E_(b) (%) 178 188 200 179 Strain sweep(60° C., 10 Hz, 5% strain, final) G′ (MPa) 3.21 3.63 3.70 3.32 tan δ0.170 0.146 0.128 0.130 ΔG′ (MPa) 4.09 4.14 3.74 3.15 Bound rubber (%)15.9 18.4 20.7 22.5

TABLE 6d Compound & vulcanizate properties, aluminum crotonate (silicacompound) 32 33 34 synthetic polymer (sample no.) 17 18 19 ML₁₊₄ @ 130°C. (final) 42.8 43.8 50.3 Tensile @ 23° C. (final, unaged) M₅₀ (MPa)2.15 2.02 2.06 T_(b) (MPa) 13.5 14.8 15.3 E_(b) (%) 272 306 318 Tensile@ 100° C. (final, unaged) M₅₀ (MPa) 2.07 1.96 1.91 T_(b) (MPa) 6.5 6.56.9 E_(b) (%) 162 171 186 Strain sweep (60° C., 10 Hz, 5% strain, final)G′ (MPa) 4.11 3.79 3.22 tan δ 0.126 0.120 0.112 ΔG′ (MPa) 4.14 3.30 2.31

TABLE 7a Compound & vulcanizate properties, zinc acrylate (carbon blackcompound) 35 36 37 38 synthetic polymer (sample no.) 9 10 11 12 ML₁₊₄ @130° C. (final) 19.7 22.9 34.4 51.5 Tensile @ 23° C. (final, unaged) M₅₀(MPa) 1.92 1.93 1.93 1.85 T_(b) (MPa) 17.3 14.5 18.8 20.2 E_(b) (%) 372310 397 394 Tensile @ 100° C. (final, unaged) M₅₀ (MPa) 1.61 1.56 1.611.66 T_(b) (MPa) 8.5 8.7 8.8 8.7 E_(b) (%) 229 239 235 211 Strain sweep(60° C., 10 Hz, 5% strain, final) G′ (MPa) 2.94 2.83 2.62 2.50 tan δ0.234 0.225 0.183 0.162 ΔG′ (MPa) 3.87 3.36 2.21 1.59 Bound rubber (%)7.6 9.1 14.5 20.6

TABLE 7b Compound & vulcanizate properties, boron acrylate (carbon blackcompound) 39 40 41 42 synthetic polymer 13 14 15 16 (sample no.) ML₁₊₄ @130° C. (final) 30.9 33.0 54.2 55.2 Tensile @ 23° C. (final, unaged) M₅₀(MPa) 1.86 1.81 1.72 1.73 T_(b) (MPa) 16.6 15.2 19.7 20.0 E_(b) (%) 349320 377 372 Tensile @ 100° C. (final, unaged) M₅₀ (MPa) 1.57 1.62 1.601.60 T_(b) (MPa) 6.4 8.7 9.3 8.8 E_(b) (%) 178 223 222 205 Strain sweep(60° C., 10 Hz, 5% strain, final) G′ (MPa) 2.67 2.45 2.27 2.27 tan δ0.211 0.196 0.154 0.142 ΔG′ (MPa) 2.97 2.20 1.32 1.12 Bound rubber (%)12.9 16.7 23.3 24.8

Examples 43-45: Aluminum Acrylate Functionalized Cis-1,4-Polybutadiene

Two preformed catalyst compositions were aged for 15 minutes at roomtemperature prior to use. The compositions were prepared by mixing, indry, N₂-flushed bottles, methylaluminoxane in toluene, 1,3-butadienesolution, neodymium versatate in cyclohexane, diisobutylaluminum hydridein hexane, and diethylaluminum chloride in hexane. The amounts of thecomponents used for each were as follows:

TABLE 8 Catalyst ingredients Catalyst A Catalyst B Concentration AmountConcentration Amount methylaluminoxane 1.45M 13.2 mL 1.45M 14.6 mL1,3-butadiene solution 21.3% (by wt.) 3.0 g 22.0% (by wt.) 3.2 gneodymium versatate 0.537M  0.36 mL 0.537M  0.39 mL diisobutylaluminumhydride  1.0M 3.73 mL  1.0M 4.43 mL diethylaluminum chloride 1.07M 0.72mL 1.07M 0.79 mL

To a N₂-purged reactor were added 1.23 kg hexane, 3.00 kg 1,3-butadienesolution (21.3% by wt.), and Catalyst A. The reactor jacket temperaturewas set to 60° C. and, ˜60 minutes after addition of catalyst, thepolymerization mixture was cooled to room temperature. This polymer isdesignated as sample 43 below.

A similar polymerization was carried out with 1.32 kg hexane, 2.91 kg1,3-butadiene solution (22.0% by wt.), and Catalyst B. The resultingpolymer is designated as sample 44 below.

Portions of samples 43 and 44 were coagulated with isopropanolcontaining BHT.

An additional portion of the sample 44 polymer cement was transferred toa bottle and reacted with the diisobutylaluminum acrylate from Example 1at an 80:1 molar ratio (acrylate-to-Nd). This bottle was agitated for˜30 minutes in a 50° C. water bath before water (1 g per 400 g polymercement) was added to terminate the pseudo-living chain ends. This cementalso was coagulated with isopropanol containing BHT.

Each of samples 43-45 was drum dried. Properties of the control polymers(samples 43 and 44) and the functionalized polymer (sample 45) aresummarized in Table 9, with cold flow measurements representing samplethicknesses at the conclusion of 8 minutes.

TABLE 9 Properties of polymers from Examples 43-45 43 44 45 M_(n)(kg/mol) 162 135 143 M_(w)/M_(n) 1.76 1.67 1.74 M_(p) (kg/mol) 204 192202 cis-1,4 (%) 93.8 93.6 93.5 trans-1,4 (%) 5.7 5.9 6.0 vinyl content(%) 0.5 0.5 0.6 cold flow (mm) 2.45 1.84 3.16

Examples 46-48: Filled Compositions and Vulcanizates

The polymers from Examples 43-45 were used to make filled compositions(compounds), employing the carbon black formulation from Table 5b withthe following modification: 20 phr of the synthesized polymer wasreplaced by an equivalent amount of polyisoprene. Vulcanizates wereprepared from the filled compositions using procedures describedpreviously, and results of physical testing on those filled compositionsand vulcanizates are summarized in the following table.

TABLE 10 Compound & vulcanizate properties, aluminum acrylate (carbonblack compound) 46 47 48 synthetic polybutadiene 43 44 45 (sample no.)ML₁₊₄ @ 130° C. (final) 74.3 57.9 76.4 Ring Tensile @ 23° C. (final,unaged) M₁₀₀ (MPa) 2.41 2.30 2.18 T_(b) (MPa) 17.57 17.64 18.28 E_(b)(%) 456 475 503 Ring Tensile @ 100° C. (final, unaged) M₁₀₀ (MPa) 2.222.11 2.00 T_(b) (MPa) 10.00 10.40 10.73 E_(b) (%) 358 383 415 Strainsweep (50° C., 15 Hz, 3% strain, final) G′ (MPa) 3.99 3.44 3.58 ΔG′(MPa) 3.41 2.68 2.81 tan δ 0.1228 0.1218 0.1193

That which is claimed is:
 1. A terminally functionalized polymerprovided by a process comprising reacting a terminally active polymerthat comprises polyene mer with an α,β-ethylenically unsaturatedcompound having the general formula

where each R independently is a hydrogen atom or C₁-C₁₀ alkyl group, Mis a group 2-13 element, y and z are integers with the provisos that zis not zero and y+z is equal to a valence of M, and each X independentlyis R¹, OR¹, OC(O)R¹, C(O)OR¹ or NR¹ ₂ in which each le independently isa C₁-C₃₀ alkyl group, thereby providing said terminal functionality tosaid polymer.
 2. The polymer of claim 1 wherein said terminally activepolymer comprises polydiene mer.
 3. The polymer of claim 2 wherein saidterminally active polymer is provided in the presence of alanthanide-based catalyst.
 4. The polymer of claim 1 wherein saidterminally active polymer further comprises vinyl aromatic mer.
 5. Thepolymer of claim 4 wherein said terminally active polymer is provided inthe presence of an anionic initiator.
 6. The polymer of claim 1 whereinz is 1 and wherein M is B and y is 2, M is Al and y is 2, or M is Zn andy is
 1. 7. The polymer of claim 1 wherein said α,β-ethylenicallyunsaturated compound has the general formula

where R″ is a hydrogen atom or C₁-C₃ alkyl group, M is a group 2-13element, y and z are integers with the provisos that z is not zero andy+z is equal to a valence of M, and each X independently is R¹, OC(O)R¹,C(O)OR¹ or NR¹ ₂ in which each R¹ independently is a C₁-C₃₀ alkyl group.8. The polymer of claim 1 wherein said α,β-ethylenically unsaturatedcompound has the general formula

where R′ is a C₁-C₁₀ alkyl group, M is a group 2-13 element, y and z areintegers with the provisos that z is not zero and y+z is equal to avalence of M, and each X independently is R¹, OR¹, OC(O)R¹, C(O)OR¹ orNR¹ ₂ in which each R¹ independently is a C₁-C₃₀ alkyl group.
 9. Thepolymer of claim 1 wherein said α,β-ethylenically unsaturated compoundhas the general formula

where each R′ independently is a C₁-C₁₀ alkyl group, M is a group 2-13element, y and z are integers with the provisos that z is not zero andy+z is equal to a valence of M, and each X independently is R¹, OR¹,OC(O)R¹, C(O)OR¹ or NR¹ ₂ in which each R¹ independently is a C₁-C₃₀alkyl group.
 10. The polymer of claim 7 wherein z is 1 and wherein M isB and y is 2, M is Al and y is 2, or M is Zn and y is 1.